Confused a bit. I recently got a 98 5.9 ZJ and the previous owner swapped in a NP231 model year 2000. When I go to shift it parked with engine idling, there's hard core grinding going on. If I try hard enough which is bad I'm sure, it will shift thru. IF the engine is off. I can shift it through the gears without grinding. What would be causing the t case to grind if the vehicles parked??

 

Do jeeps that come from the factory with a NP231 need to be shut off to switch from 2 to 4?

 

semi normal, not really, but it is normal if the linkage isnt adjusted right. Mine does the same thing.